The only one I can think of for this is Learning to Live Half a Life (http://princess-aleera.livejournal.com/121125.html) by princess-aleera: "John drinks. A lot. And it's exhausting for Dean to try and keep the family together, it wears him out to make sure school's okay for Sammy and himself and then clean up after their father when he's finally passed out on the bed or the bathroom floor. Michael is a safe haven. Michael is different. As long as Dean does what Michael tells him to do, he can pretend everything's okay. At least for a little while." (I'm pretty sure the Michael here is an OC, not the angel :))